From the article:
What is known is that Yule, or “Yuletide” was an ancient winter festival, that was celebrated by the ancient Germanic tribes, and later specifically adopted into the Christian festival of Christmas. Most indication are that it was a specifically religious festival, likely originally associate with death, rebirth and ancestor worship, that easily reaches back into the Bronze Age. An animal sacrifice was likely offered to hasten the coming of spring. Many scholars believe that the principle deity venerated in connection with this ancient holiday during historical times was Odin, in his guise as Jólnir (Old Norse "yule figure"), master of the Wild Hunt. Over time, Yule festivals became more celebratory, became associated with feasts, the first drinking of midwinter ale and displays of largesse, particularly gift-giving from master to servant. These customs seem to have had little to do with the original somberness of the cult of the dead, and may have been adapted from exposure to the Roman mid-winter celebrations of Saturnalia.
Our thanks to Lady Catriona Fionnaghal nic Elphinstone for forwarding the link.